Great find....excellent article.
This can be done with out another canoe near by, by one person, or two is better, and both wearing PFD even better yet.
Canoe upside down....swim under, place feet on one gunnel and grab the other side with your hands...lift as best as you can, kick up and flip with your hands.
Idea is to "roll over in the air"......when it lands should be floating. but may have some of water in it.
Now slither back in....if two people are there, one hold steady.... and you slither in for the other side.....repeat.
Then using your hands scoop water out ......now go find your stuff.
If you were prepared, you will have a spare paddle ties inside.
This is actually not that difficult, and does work.....
And like the article says, summer on a calm lake in swim suits and PFD's is the time to practice.
Fast moving rivers, in waders and heavy coat.....just t=stay with the boat till you can get to shore.